The service's top general was at Fort Carson last week as leaders wrapped up a two-week war game that simulated battles in Europe.

In a departure from the policies of a general he replaced in August, Milley said he's embracing the National Guard and Army reserve to fill in for an active-duty force that's in the midst of losing 70,000 troops to budget cuts.

"The Army is a million-plus, it's not 450,000," Milley said, rattling off the numbers of the combined force of the Army and its part-time forces against the shrinking active-duty roster. "I think of the Army as a single entity that comes in three forms."

The Guard was heavily used in Iraq and Afghanistan, but leaders complained about the long time it takes to get part-time troops ready for war. Milley said he hopes to overcome that by increasing training for the Guard and by integrating active soldiers in their ranks.

"We're really taking a page out of the Air Force book," Milley said.

The Air Force has used part-time flying units to fill wartime needs, citing the significant payroll savings of airmen who work one weekend a month and two weeks a year.

The Army, though, dropped tighter integration of part-time troops after experiments in the 1970s and '80s proved troublesome when troops mobilized for the Persian Gulf War.

Now, Milley is mulling the return of those "round-out" units. That would mean active-duty units would contain a reserve or Guard contingent that could be called up for conflicts. But making that work means Guard troops will need a level of training similar to their full-time comrades. Getting there will require more deployments for part-time troops and more monthlong rotations for intensive training in California or Louisiana, he said.

"I want to make sure we are operationally using the Guard," Milley said.

Milley said he also wants part-time troops to spend more time in uniform, upping the 39-day training standard that's been in place for more than a century.

Much of what Milley is calling for was outlined in recommendations late last month from the National Commission on the Future of the Army. That panel's 200-page report called on leaders to drop distinctions between the Army's active-duty and reserve components. It remains under study at the Pentagon.

The push to beef up the part-time force comes as leaders express increasing alarm over a rise in Russian military strength that accompanied that nation's aggression in Ukraine. A recent Rand Corp. study commissioned by the Defense Department found the U.S. and its NATO allies lacked strength to be more than a speed bump against a determined Russian attack on Baltic nations.

"The situation in Europe is very serious, and we all know that," Milley said.

Milley's chosen answer to rising tension is Fort Carson's 4th Infantry Division, which is in charge of training American and allied troops in Europe. The training exercise at Fort Carson, actually a complex video game to challenge commanders leading simulated ground troops, focused on Europe.

Beefing up U.S. forces in Europe is more than a planning exercise. Milley said the Army is adding "pre-positioned" gear in Europe, that soldiers flown from the U.S. can quickly use if war breaks out.

He's also setting up a succession of Army brigades that will rotate through Europe for training under the 4th Infantry Division, building the readiness level across the Army for fighting across the Atlantic Ocean.

And the two weeks of work at the post were aimed at getting Fort Carson's brass ready for war in Europe. Leaders were faced with an aggressive nation invading the fictional state of "Etropia." Fort Carson leaders had to assemble the Army's response and battle to restore prewar borders.

"It's important that we train the 4th Division so it can deter (the threat)," he said.